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BrianG
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04.28.2007, 02:16 PM

Serum: yeah really! Where are my priorities!? :)

Griffin: I couldn't find an exact part number match, but I did find a partial match and when I looked at the package, it was a transistor. So, I suppose I should have dug further. My bad. :dft001:. And even then, unless the LDO regulator IC specifically has FET outputs, you shouldn't parallel them. In this case, I wouldv'e used a pass transistor to boost the current.

HOWEVER! I did some testing that should really "put the nail in the coffin" for the argument to disable the ESC's BEC. Using several resistors, I hooked up a small 250mA load to the 5v output of the ESC BEC.

On 2s, the regulator circuit got warm, ~100*F, and seemed to hold that temp.
On 3s, the regulator circuit got very warm quickly to around 140*F within 20 seconds.
On 4s, the regulator circuit got very very warm very quickly to over 160*F within 20 seconds.

Don't forget, the MM uses the PCB traces as a heatsink. So, all that heat warming up all the surrounding components on the "brains" board. I don't what USB controller or motor controller ICs they use, but I highly doubt they are meant to handle that kind of heat. And these devices aren't even on a heatsink.

So, the lesson learned here is:

ANYTHING over 2s, use an external UBEC.
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celticclown
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04.30.2007, 11:36 PM

for those of you with ESC's taken apart. Has anyone considered stacking FET's to get more power and reliability out of thier esc. You would obviusly need a new case or at least modify the original to fit. A full set of double stacks should make things work much better. I had to do this on my mini-z. went from 2 FET's to 8. My punch went through the roof and it can now handle significantly heavier loads (bigger motor) and more voltage.
   
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BrianG
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05.01.2007, 09:59 AM

Yes, GriffinRU has said he has/can do this. Basically, unless you are running a hot setup, 100A and 4s is usually plenty. Most people would rather run higher voltage and less current.
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